System of control for induction-motors.



I A. SGHERBIUS. I I SYSTEM. or common FOR INDUCTION MOTORS. I APPLICATION FI-LIED mm: 27,-19os.

1,059,771,. Pate tedn22,- 1913;

OFVBADEN, swrTzEnLAnn'.

*AR'TfnUR scnnasrus.

OFFIC srsrminol con'moL r03 mmrcnoiv-moroasl To all whom it may cone-em:

Be it known that- I, AiirrHU i SCHERBIUS, a

citizen of. the Swiss Confederation, and resiv embodiment of this invention; v a

dent of Baden, Switzerland, have invented a certain new and useful System of-Control for Induction-Motors, of which the followtrot-or of asynchronous machines with a commutator, thedifterent segments of which are mg is a'spe'cifica-tion.

This invention relates to the control 0 alternating current machines. It "hasbeen proposed for this purpose to provide the connected resistances, andto introduce into this commutator curientshaving voltages proportional to the line voltage, or

currents proportional to the line current;

These machines have the drawback that the commutator increasesthe cost of construc- .t-ion, leads to sparking, and operation is easily affected by such accidental conditions brushes upon Accordingto the present invention, the

commutator is separate from theasynchronous machine, and is carried upon it rotor shaft distinct from the rotor of the motor.

The segments of the commutator are con-' nected to the field windings of a separately driven commutator generator, the brushes of which are connected to the slip rings. of

the asynchronous machine. The vbrushes which co-act with the commutator of the rotor shaft are supplied. With current at voltage proportionate to the line voltage, and

of the same frequency. The'rsult, assum- -ing the rotor of the asynchronous machine to be revolving at a certain speed, is that' the commutator will rotate synchronously-therewith, and will therefore feedinto the field windings of the commutator generator current ofzthe same frequency as the frequency of the slip currentgenerated in the rotor. ofthe'asynchronous machine. There w11lthere-' fore be produced in the armature of the commutator generator current ofslip frequency,

. and of voltage dependent upon the speedof this generator, which voltage can be used for regulation of the asynchronous machine. Thus, if its value be less than that of the slip voltage, the latter will have a positive value, and the asynchronous machine will run below synchronism. If its value is equal to-the slip voltage, the machine will run synchronously; and if its value is greater than the slip voltage, the asynchronous ma- Specification of Letters Patent. Application filed June 27, 190.8. Serial N 0. 440,695.

carries a commutator Bruslies 9 connected bbear upon the commutator.

. tain current,

sired to controlthe speed of:

P tent ai r.22,1913.

chine will run above synchronism, that "is, as-a generator. I a a In Figure 1 1S diagrammatically shown an A isan asynchronous three-phase machine. Connected to three phase mains b,1t'h'asfield \ViiltltllgSti and slip rings 0. The rotor and slip rings are IIIOHIItQd upon a'shaft e, which which are connected bv-leadsato slip rings .s-,and .are interconnected'by resistancesw.

The slip rings 8 are connected by leads -71 to the exciting w ndingfE of a connniitatoigenei'ator 0,

B, the segments 7 of by leads fto the mains the .arinature of which, 2', is connected to a1 shaft 122;, which may beadriven-u Brushes j and leads Z connect the armature zYto "the slipi'ings-c. i 1 at:

The operation is as follows :-rSupp'ose the machine A running 1:15 v iii mOtOr, J A cering a certain frequency and voltage, that is, the slip value, will be generated in the rotor of the machine .A. At the-sametime, since the commutator B is 3180;.lI1Q11l1tCd; onf'the shaft 6, the current 9 will be converted by the coinmutationfrom line frequency at these brushes; to slip fre quency atthe slip rings #3. .H IlCe the ,machine C will be excited-by currentsof the that is, the slip, current, have supplied by the brushes same frequency as the f feq uencyin the rotor g.

of A, and king a commutator generator, will supply at its brushes ;7' current still at the same frequency, independently. of the speed at which the armature, .z' is, driven. The

voltage of the current thus produced byrG.

can be varied by changing, thespeec llofjthe shaft m. Suppose, l10 e 1, tl l1lI ll is dethat is, the speed of the machine A. If. the voltage of the currentgii ei fout by C. is in-., creased. the slip voltage .also, increases and so the slip must increase and'thtjreforethc speed gradually decreases. Eventuallythe slip becomes 1127. that is when the voltage the 'shaft c.

ice

from C wholly neutralizcs the yoltage gen-.

erated-in the rotor of the macll iiicpandthe machine runs s \'nclii'onoiisly'. now 'increasing the voltage generated by C" the machine. can be caused torun above synchronism. If it driven externally beyond its synchronous speed then like every asynchronous machine it can also run as a gen erator.

will be understood that the function of' B is to insure obtaining of a voltage used for opposing the rotor-voltage of the asynchronous machine of thesamefrequency as 5 'the current in the rotor, whatever the speed of the machine. The function of the mabination, an induction machine including a rotor and a stator with windings thereon, a

- commutator machine vincluding a rotor and astator, with windings on said stator, a

commutator with windings in connection therewith and brushes adapted to bear on the surface of said commutator, a mechani cal connection between the rotor, of the induction machine andv the commutator, electrical connectionsfrom the rotor of the 'commu'tator to the stator-of the commutatormachine and from the brushesof the commutator to the stator .of and furtherelectrical connections between the rotor of the commutator machine and the rotor of the induction machine as set 59 '1 2. In. combination, polyphase leads, an asynchronous machine, field windings on said machine, connected to aforesaid leads, a

wound rotor on said' machine, slip rings 'connected to the, windings of said rotor, a shaft extending-'from said rotor, a commutator mountedthereon, slip rings on said shaft, connected to the segments of aforesaid commutator, brushes co-acting with said'seg ments, and supplied with. a voltage prop'or'- tional to the voltage of aforesaid mains, a commutator machine, exciting windings I said machine, connections from said wind-i ings to the slip rings of said commutator, a commutator on said commutator machine, brushesbo-acting therewith, and connections. from said brushes to the slip rings of the asynchronous machine, as set forth.

3. .In dynamo electric machinery in combination an induction'machine including a fixed and movable part acommutator ma-' chine also including a fixed and movable part together with a commutator and brushes being relatively movable, a mechanlcal connection between .gthe movable parts of the induction machine y-"and the frequencvconverter and electrical the induction machine;

frequency converter comprising a commutator and brushes, said connections between the fixed part of the commutator machine add .one part of'the' said converter, electrical connections between the other part of the converter and one part of the induction machine and, further electrical connections between the "other -part of saidcommutator machine and. the other part of the induction machine; asset forth. i f Y v 4. Indynamo electric machinery in' combination an induction machine including a chine; also-including a' fixed and movable comprising a commutator and brushes, said commutator and brushes being relatively movable, a mechanical connection between the movable parts-of the induction machine and the frequency converter and electrical connections between the-fixed part of the commutator machineand one part of the said -conver'ter, electrical connections tween the other-partof the-converter and the fixed part of the induction machine an d fu'rther electrical cohnec tionsbet-ween the "movable .part of said commutator 'machine and the movable part of the induction ,machine as set forth.

machinery in combination polyphase leads, a stator, a rotor, field windings on said sta-' tor, electrical connections between said field windings and aforesaid leads, said rotor, slip-rings, electrical connections 1 between said slip rings'and said rotorwindc hanical connectionbetween said conimutator, said rotor and said'further slip rings, windings on said shaft, electrical connecmy'hand in presence of two witnesses.

' VARTHUR SCHERBIUS.

lVitnesses GEO. C. LEBER,

- A. LIEBERKNECHT.

part together with a frequencyconverter.

5.,In dynamo electric, alternating current tions between said windings and the seg-' In testimony whereof I have hereunto set I fixed and movable part a commutator maings, a commutator, further slip rings, me-

on and electrical connections from said fura 

